1. Field of the Invention
The present invention relates to a projection apparatus having a temperature controlling system. More particularly, the present invention relates to a technology for generating or radiating heat in response to different ambient temperatures to maintain the operation of a projection apparatus under the desired working temperature.
2. Descriptions of the Related Art
In designing most projection systems, a cooling system is important in maintaining the operation of interior elements under a certain temperature and extending service life of the interior elements, especially for large scale, heavy duty, or high heat producing projection systems. More specifically, the interior elements can be categorized into a lower temperature group and a higher temperature group when the projection system operates. A proper design allows the cooling liquid to first flow through the low temperature group of elements and then through the high temperature group of elements, thereby reducing the temperature of the projection system and maintaining the system at operation under a mean temperature. Thus, to maximize cooling efficiency, the cooling system needs to be adjusted and improved according to the inner optical arrangement of the projection system.
Liquid cooling and air cooling are the two common ways for cooling projection systems. Either method of liquid or air cooling adopts the circulation of fluid to reduce the interior temperature of the projection system. However, the liquid cooling method is more effective in equalizing temperature of interior components and generating less noise. At the same time, the liquid cooling method requires more space and is usually applied to a projection system that is operated in a larger place, such as a public place, mass transition station, or an airport. It is understandable that, in general, the characteristics of the air cooling method are just as adverse as those of the liquid cooling method. As a result, a common cooling medium used for liquid cooling is water because of its high specific heat and capability of absorbing a large amount of heat without obvious temperature fluctuations. In conjunction with the use of a fin and/or a fan to expand the heat dissipation area, the efficiency of heat dissipation of liquid cooling can also be improved.
Limited by the working temperature of the interior components, the present projection system could only operate between 5° C. to 35° C. to ensure stability at normal operation and fulfill the expected service life of the projection system. When the ambient temperature ascends above the upper temperature limit, the cooling capability of the projection system requires reinforcement to prevent internal components from continuously generating heat with a positive value, thereby reducing the efficiency and service life of the apparatus. On the contrary, when the ambient temperature descends below the lower temperature limit, the projection system requires heat to raise the temperature of the internal components to a working temperature so that the projection system may operate normally.
There are many improved liquid or air cooling technologies for projection systems in the market. Even so, there is neither a competitive technology for raising the temperature of the system from a very low ambient temperature to a normal working temperature, nor a technology that efficiently cools the system at a very high ambient temperature and heats the system at a very low ambient temperature.
Therefore, the research and development of a liquid cooling technology for use in adjusting the interior temperature of the projection apparatus is needed. In other words, an advanced temperature controlling system is required in the market. The system should be able to: (1) raise the temperature of the components from an extremely low ambient temperature to a working temperature to start up the system, (2) reduce the temperature of the components to function under high ambient temperatures (3) stop the cooling process when the temperature is normal, (4) reduce the generation of noise and (5) consume less power.